The present invention relates to a method of cleaning or maintaining the cleanliness of a laser optical compartment and to a decontamination apparatus for a laser system and especially to a laser decontaminate apparatus and method attached within a laser system for absorbing contaminants from gases used in the system.
The fundamental components of a laser are a resonator, a laser medium, an output coupling mechanism, and a laser optical compartment housing the aforementioned components and other auxiliary equipment. A laser resonator basically consists of two resonator reflectors between which light travels back and forth. The region between the two reflectors is termed a "resonator". A laser gain medium within the cavity amplifies the light as it repeatedly traverses the cavity. Laser gain media are typically either solid state (such as Nd:YAG), gas (such as CO.sub.2) or liquids (such as dye-bearing solvents). A gas laser has as its lasing medium a gas contained or flowing within the cavity between the cavity reflectors. A solid state laser places a solid crystal rod or the like within the laser cavity between the resonator reflectors. A liquid laser may include a dye/solvent mixture within a cell bounded by glass windows. Laser optical compartments are often closed or sealed to prevent inadvertent personnel access or to exclude contamination or perturbation by external forces. In almost cases, the laser compartment contains either active or passive gases through which the laser beam propagates. As a result of imperfect cleaning, seal leakage or offgasing of structural or optical materials, volatile contaminates are invariably evolved into the gas volume. Because of the high optical powers which exist within the resonator, these contaminants often lead to optical damage of components on which the laser beam impinges.
In the past, various types of materials and cleaning processes have been used to make laser systems in order to prevent or reduce contamination within the gas volume within the lasers but it is still common to simply remove the gases periodically and replace them to thereby remove the contaminants. This is both expensive and inconvenient and is often ineffective in eliminating optical damage when rates of contamination are unknown.
The present invention is directed towards an apparatus and method to remove contaminant vapors from a laser optical compartment to thereby prevent optical damage or loss of efficiency resulting from deposition of solid or liquid films from the gas since many of the materials that could be used for removing contaminants are themselves a contaminant or dirty and cannot be used in a laser optical compartment. The present invention is directed towards an apparatus which allows materials which are required for absorbing certain type of contaminants to be used in a manner that they can absorb the contaminants without contaminating the laser compartment gas volume.